An existing widely-used screw cap container may be capped by screw-fastening a female screw portion provided in a cap with a male screw portion provided in a mouth tubular portion of a container main body.
Concrete examples of such an existing screw cap container may include the one including the container main body, which has a container mouth provided on an outer circumferential surface thereof with screw threads formed as a plurality of ridges, and the cap, which is provided on an inner circumference thereof with engagement portions configured to engage with the screw threads. The existing screw cap container permits opening and closing operations with a rotational angle that is smaller than a full rotational angle and, once being capped, is not easily disengaged (refer, for example, to Patent Literature 1).